Introduction to Basic Manufacturing Processes and ... - always yours

324 Introduction to Basic Manufacturing Processes and Workshop Technology
bare electrode and molten pool remain completely submerged under blanket of granular flux.
The feed of electrode and tube is automatic and the welding is homogenous in structure. No
pressure is applied for welding purposes. This process is used for welding low carbon steel,
bronze, nickel and other non-ferrous materials.
To ground
Finished weld
surface
Solidified flux
To power supply
Welding
electrode
Welding flux feed tube
Weld direction
Base material
Weld material
Granulated
welding flux
Weld backing
if required
Fig. 17.20 Schematic submerged arc welding process
17.6.5 Gas Tungusten Arc Welding (GTAW) or Tungusten Inert Gas Welding
(TIG)
In this process a non-consumable tungsten electrode is used with an envelope of inert shielding
gas around it. The shielding gas protects the tungsten electrode and the molten metal weld
pool from the atmospheric contamination. The shielding gases generally used are argon,
helium or their mixtures. Typical tungsten inert gas welding setup is shown in Fig. 17.21.
Tungsten
electrode
Electrode
holder
Regulator
Gas passages
Insulating
sheath
Shielding gas
Welding
power source
Inert
gas
supply
Work
Fig. 17.21 Tungsten inert gas welding setup
Electrode materials
The electrode material may be tungsten, or tungsten alloy (thoriated tungsten or
zirconiated tungsten). Alloy-tungsten electrodes possess higher current carrying capacity,
produce a steadier arc as compared to pure tungsten electrodes and high resistance to
contamination.